Wheel assemblies are installed on bottoms of cabinets, cases and the like which are easy to be moved and carried in everyday life. For example, people usually carry suitcases on business trips or personal travels. In some suitcases, the bottoms are installed with two or four wheel assemblies so that the suitcases can be dragged by the users.
However, wheel assemblies of a suitcase are prone to be damaged, sometimes rendering the whole suitcase useless.